. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. Clieek pouches of the Canada Nat ( Geomys bursarius). Some genera, as, for example, the Canada rat (jfig. 270.) are remarkable for the pos- session of capacious cheek pouches, in which considerable quantities of food can be stored up, and which, like the crop of birds, may be considered as reservoirs, wherein nutriment can oe retained preparatory to its introduction into the stomach. The type of stomach most common in this order is the following: the stomachal bag is formed by two distinct pouches, which are more or less
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. Clieek pouches of the Canada Nat ( Geomys bursarius). Some genera, as, for example, the Canada rat (jfig. 270.) are remarkable for the pos- session of capacious cheek pouches, in which considerable quantities of food can be stored up, and which, like the crop of birds, may be considered as reservoirs, wherein nutriment can oe retained preparatory to its introduction into the stomach. The type of stomach most common in this order is the following: the stomachal bag is formed by two distinct pouches, which are more or less separated from each other ; one portion, situated to the left of the cardia, is placed longitudinally, and is generally of a cylindrical or conical shape. This portion is frequently larger than the right portion ; it is lined internally with a thick epidermis, which terminates suddenly, and clearly indicates by its margin the boundaries of this compart- ment of the stomach. The right compartment, •which is situated more transversely and further back, is of a conical shape, the apex of the cone terminating at the pylorus. This second portion has its walls thicker and more mus- cular than the former ; its mucous membrane is not lined with epidermis, but presents the ordinary appearance. The distinction be- tween these two portions is indicated ex- ternally by a constriction. The oesophagus enters the first compartment very near to the point where it communicates with the second. Such may be said to be the typical form of the stomach in this extensive order, but many families recede from it to a greater or less ex- tent. In the squirrels (Scii/rus) for example, the stomach is not divided into separate cavities, but is of a pyriform or oval shape, giving off a conical or cylindrical portion, which ter- minates in the pylorus. The first compart- ment is lined internally with a thick epi- dermis, which forms two oval lips, as it is prolonged around the opening into the second com
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